Technical Field
The present disclosure relates to a positioning system and method thereof, more particularly to a system for automatically and precisely positioning a robotic arm and a method thereof.
Background Art
When a robotic arm is moved, a traditional control apparatus just provides a relative measurement position but not an absolute measurement position, and it means that an application which depends on absolute coordinate of the control apparatus for correct operation requires further complicated computation to continuously maintain a position track of the control apparatus. In addition, the control apparatus must be re-positioned periodically, or else the positioning error of the control apparatus will be accumulated continuously, it will become a risky condition for the application soon.
An optical type positioning system is usually adopted to position the robotic arm in an operating space of the robotic arm. During operation of the optical type positioning system, a workpiece or positioning auxiliary tool must be marked with optical positioning points for quickly positioning, and cameras must be installed as auxiliary apparatuses. These cameras must be calibrated in advance to obtain intrinsic parameters and extrinsic parameters for reducing image distortion.
The intrinsic parameters are generated based on a pin hole model, and a zoom lens with different focus length has different intrinsic parameters. During the positioning procedure of the optical type positioning system, an intrinsic parameter calibration is performed first and the obtained intrinsic parameters are multiplied with the coordinate matrix of the robotic arm and extrinsic parameter matrixes of the cameras to obtain coordinates of the optical positioning points, so that the error accumulation is easily generated.
To sum up, the problems of complicated robotic arm positioning process and easily generating error accumulation exist in the traditional positioning technology for long time, and what is need is to provide an improved technology solution to solve the problems.